the forumad ophiolite in the northwestern part of the sabzevar region has embraced the largedepleted harzburgites and dunitic bodies associated with podiform chromitites. in some deposits, chromitegrains have segregated as nodules. the stretched shape along with high cr2o3 and tio2 contents are thecharacteristics of the nodules. compared to the other tethyan nodular chromites, the forumad nodul...

biogeochemical investigation on s. orientalis, a flora growing on the soils derived from serpentinized dunite in the forumad area, sabzevar ophiolite has been conducted in order to examine the plant-soil relationship in chromite prospecting. due to engagement of cr in the chromite crystal structure and its non-essential role in the plant’s life cycle, ni was used as pathfinder element in biogeo...

Tested water samples taken from the ophiolite region of Forumad show that most of the concentrations of calcium, magnesium, sodium, sulfate, potassium, bicarbonate, and nitrate elements are in the standard range. Hydrogeochemical studies of the water samples show the existence of magnesium sulfate, chloromagnesium, and chlorosodium. Results of measuring the physical properties of the water show...

Structural field relations, petrologic and geochemical studies, and radiometric age aualysis of metamorphic rocks at the base of the Brooks Range ophiolite provide a record of the time, tectonic setting, and initial conditions of ophiolite emplacement during the Middle Jurassic western Brookian orogeny. The metamorphic sole of the Misheguk, Siniktanneyak, and Avan Hills ophiolite bodies is tran...

(40)Ar/(39)Ar dates of emplacement-related metamorphic rocks beneath the Samail ophiolite in Oman show that cooling to <525 degrees C occurred within approximately 1 million years of igneous crystallization of the ophiolite. This unexpectedly short time span and rapid cooling means that old, cold continental or oceanic lithosphere must have been adjacent to the ophiolite during spreading and th...

The Ophiolite Terrane of the Southern Chewore Inliers is comprised of two related, but lithologicallyand geochemically-distinct groups. The Maunde Ophiolite Group comprises a suite of lithologies similar to those within Phanerozoic ophiolites. The Kaourera Island Arc Group contains a suite of silica-variable, extrusive lithologies similar to those within present-day island-arcs. Geochemical ana...

New geochronological data and published structural and stratigraphic data show that two distinctly different ophiolitic assemblages formed in general proximity to one another at nearly the same time and were subsequently imbricated along a regional thrust zone. The Josephine ophiolite constitutes a complete oceanic crust and upper mantle sequence which lies within the western Jurassic belt of t...

The Kings-Kaweah ophiolite belt of the southwestern Sierra Nevada Foothills was generated in two pulses of mid-oceanic-ridge basalt (MORB) magmatism. The first was in the Early Ordovician, which resulted in the generation of a complete abyssal crust and upper mantle section. The crustal section was rendered from convecting mantle whose Nd, Sr, and Pb isotopic systematics lie at the extreme end ...

Two tectonic scenarios have been proposed for genesis and emplacement of the Oman ophiolite. One suggests that the ophiolite was generated at a spreading center, the other suggests generation within an intraoceanic arc. An integrated thermal and kinematic model of the temperature, stress, rock type, and displacement fields during early stages of the emplacement ofthe Oman ophiolite was develope...

Analysis of internal structures of the Brooks Range ophiolite at the three largest and well-exposed klippen reveals a NE-SW structural grain that may parallel the original axis of magmatism of a slow spreading marginal ocean basin. Sub-parallel directions of lattice·fabrics in olivine of mantle peridotite and shape fabrics in pyroxene and plagioclase of layered gabbro indicate that asthenospher...